scholarly journals Inverse Perron Values and Connectivity of a Uniform Hypergraph

10.37236/7410 ◽  
2018 ◽  
Vol 25 (4) ◽  
Author(s):  
Changjiang Bu ◽  
Haifeng Li ◽  
Jiang Zhou
Keyword(s):  
Connected Graph ◽  
Symmetric Design ◽  
Uniform Hypergraph ◽  
Edge Connectivity ◽  
Resistance Distance ◽  
Isoperimetric Number

In this paper, we show that a uniform hypergraph $\mathcal{G}$ is connected if and only if one of its inverse Perron values is larger than $0$. We give some bounds on the bipartition width, isoperimetric number and eccentricities of $\mathcal{G}$ in terms of inverse Perron values. By using the inverse Perron values, we give an estimation of the edge connectivity of a $2$-design, and determine the explicit edge connectivity of a symmetric design. Moreover, relations between the inverse Perron values and resistance distance of a connected graph are presented.  

scholarly journals Maximum Reciprocal Degree Resistance Distance Index of Bicyclic Graphs

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Gaixiang Cai ◽  
Xing-Xing Li ◽  
Guidong Yu
Keyword(s):  
Connected Graph ◽  
Extremal Graph ◽  
Resistance Distance ◽  
Bicyclic Graphs

The reciprocal degree resistance distance index of a connected graph G is defined as RDR G = ∑ u , v ⊆ V G d G u + d G v / r G u , v , where r G u , v is the resistance distance between vertices u and v in G . Let ℬ n denote the set of bicyclic graphs without common edges and with n vertices. We study the graph with the maximum reciprocal degree resistance distance index among all graphs in ℬ n and characterize the corresponding extremal graph.

scholarly journals Some Bounds for the Kirchhoff Index of Graphs

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Yujun Yang
Keyword(s):  
Connected Graph ◽  
Planar Graphs ◽  
Independence Number ◽  
Clique Number ◽  
Upper Bounds ◽  
Electrical Network ◽  
Lower And Upper Bounds ◽  
Kirchhoff Index ◽  
Resistance Distance ◽  
Fullerene Graphs

The resistance distance between two vertices of a connected graphGis defined as the effective resistance between them in the corresponding electrical network constructed fromGby replacing each edge ofGwith a unit resistor. The Kirchhoff index ofGis the sum of resistance distances between all pairs of vertices. In this paper, general bounds for the Kirchhoff index are given via the independence number and the clique number, respectively. Moreover, lower and upper bounds for the Kirchhoff index of planar graphs and fullerene graphs are investigated.

The Laplacian quadratic form and edge connectivity of a graph

2015 ◽  
Vol 30 ◽  
Author(s):  
William Watkins
Keyword(s):  
Quadratic Form ◽  
Connected Graph ◽  
Positive Semidefinite ◽  
Positive Definite ◽  
Edge Connectivity ◽  
Integral Quadratic Form ◽  
Simple Connected Graph

Let G be a simple connected graph with associated positive semidefinite integral quadratic form Q(x) = \sum (x(i) − x(j))^2, where the sum is taken over all edges ij of G. It is showed that the minimum positive value of Q(x) for x ∈ Z_n equals the edge connectivity of G. By restricting Q(x) to x ∈ Z_{n−1} × {0}, the quadratic form becomes positive definite. It is also showed that the number of minimal disconnecting sets of edges of G equals twice the number of vectors x ∈ Z_{n−1} ×{0} for which the form Q attains its minimum positive value.

scholarly journals On the Resistance Matrix of a Graph

10.37236/5295 ◽  
2016 ◽  
Vol 23 (1) ◽  
Author(s):  
Jiang Zhou ◽  
Zhongyu Wang ◽  
Changjiang Bu
Keyword(s):  
Regular Graph ◽  
Connected Graph ◽  
Spanning Trees ◽  
Regular Graphs ◽  
Resistance Distance ◽  
Strongly Regular ◽  
Resistance Matrix ◽  
Number Of Spanning Trees

Let $G$ be a connected graph of order $n$. The resistance matrix of $G$ is defined as $R_G=(r_{ij}(G))_{n\times n}$, where $r_{ij}(G)$ is the resistance distance between two vertices $i$ and $j$ in $G$. Eigenvalues of $R_G$ are called R-eigenvalues of $G$. If all row sums of $R_G$ are equal, then $G$ is called resistance-regular. For any connected graph $G$, we show that $R_G$ determines the structure of $G$ up to isomorphism. Moreover, the structure of $G$ or the number of spanning trees of $G$ is determined by partial entries of $R_G$ under certain conditions. We give some characterizations of resistance-regular graphs and graphs with few distinct R-eigenvalues. For a connected regular graph $G$ with diameter at least $2$, we show that $G$ is strongly regular if and only if there exist $c_1,c_2$ such that $r_{ij}(G)=c_1$ for any adjacent vertices $i,j\in V(G)$, and $r_{ij}(G)=c_2$ for any non-adjacent vertices $i,j\in V(G)$.

scholarly journals The first two cacti with larger multiplicative eccentricity resistance-distance

Filomat ◽  
2019 ◽  
Vol 33 (6) ◽  
pp. 1783-1800
Author(s):  
Yunchao Hong ◽  
Zhongxun Zhu
Keyword(s):  
Connected Graph ◽  
Effective Resistance ◽  
Extremal Graphs ◽  
Resistance Distance ◽  
G Value

For a connected graph G, the multiplicative eccentricity resistance-distance ?*R(G) is defined as ?*R(G) = ?{x,y}?V(G)?(x)??(y)RG(x,y), where ?(?) is the eccentricity of the corresponding vertex and RG(x,y) is the effective resistance between vertices x and y. A cactus is a connected graph in which any two simple cycles have at most one vertex in common. Let Cat(n;t) be the set of cacti possessing n vertices and t cycles, where 0 ? t ? n-1/2. In this paper, we first introduce some edge-grafting transformations which will increase ?*R(G). As their applications, the extremal graphs with maximum and second-maximum ?*R(G)-value in Cat(n,t) are characterized, respectively.

scholarly journals Resistance Distances in Linear Polyacene Graphs

2021 ◽  
Vol 8 ◽  
Author(s):  
Dayong Wang ◽  
Yujun Yang
Keyword(s):  
Connected Graph ◽  
Exact Expression ◽  
Effective Resistance ◽  
Electrical Network ◽  
Combinatorial Approach ◽  
Network Approach ◽  
Resistance Distance ◽  
Electric Network

The resistance distance between any two vertices of a connected graph is defined as the net effective resistance between them in the electrical network constructed from the graph by replacing each edge with a unit resistor. In this article, using electric network approach and combinatorial approach, we derive exact expression for resistance distances between any two vertices of polyacene graphs.

scholarly journals Isolated toughness and path-factor uniform graphs

2021 ◽  
Author(s):  
Sizhong Zhou ◽  
Zhiren Sun ◽  
Hongxia Liu
Keyword(s):  
Connected Graph ◽  
Edge Connectivity ◽  
Spanning Subgraph ◽  
K Factor ◽  
Path Factor

A $P_{\geq k}$-factor of a graph $G$ is a spanning subgraph of $G$ whose components are paths of order at least $k$. We say that a graph $G$ is $P_{\geq k}$-factor covered if for every edge $e\in E(G)$, $G$ admits a $P_{\geq k}$-factor that contains $e$; and we say that a graph $G$ is $P_{\geq k}$-factor uniform if for every edge $e\in E(G)$, the graph $G-e$ is $P_{\geq k}$-factor covered. In other words, $G$ is $P_{\geq k}$-factor uniform if for every pair of edges $e_1,e_2\in E(G)$, $G$ admits a $P_{\geq k}$-factor that contains $e_1$ and avoids $e_2$. In this article, we testify that (\romannumeral1) a 3-edge-connected graph $G$ is $P_{\geq2}$-factor uniform if its isolated toughness $I(G)>1$; (\romannumeral2) a 3-edge-connected graph $G$ is $P_{\geq3}$-factor uniform if its isolated toughness $I(G)>2$. Furthermore, we explain that these conditions on isolated toughness and edge-connectivity in our main results are best possible in some sense.

scholarly journals Bicyclic Graphs with the Second-Maximum and Third-Maximum Degree Resistance Distance

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Wenjie Ning ◽  
Kun Wang ◽  
Hassan Raza
Keyword(s):  
Connected Graph ◽  
Maximum Degree ◽  
Effective Resistance ◽  
Resistance Distance ◽  
Bicyclic Graph ◽  
Degree Of A Vertex ◽  
Bicyclic Graphs

Let G = V , E be a connected graph. The resistance distance between two vertices u and v in G , denoted by R G u , v , is the effective resistance between them if each edge of G is assumed to be a unit resistor. The degree resistance distance of G is defined as D R G = ∑ u , v ⊆ V G d G u + d G v R G u , v , where d G u is the degree of a vertex u in G and R G u , v is the resistance distance between u and v in G . A bicyclic graph is a connected graph G = V , E with E = V + 1 . This paper completely characterizes the graphs with the second-maximum and third-maximum degree resistance distance among all bicyclic graphs with n ≥ 6 vertices.

scholarly journals Maximum Reciprocal Degree Resistance Distance Index of Unicyclic Graphs

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Gai-Xiang Cai ◽  
Xing-Xing Li ◽  
Gui-Dong Yu
Keyword(s):  
Connected Graph ◽  
Extremal Graph ◽  
Resistance Distance ◽  
Unicyclic Graphs

The reciprocal degree resistance distance index of a connected graph G is defined as RDRG=∑u,v⊆VGdGu+dGv/rGu,v, where rGu,v is the resistance distance between vertices u and v in G. Let Un denote the set of unicyclic graphs with n vertices. We study the graph with maximum reciprocal degree resistance distance index among all graphs in Un and characterize the corresponding extremal graph.

Degree Kirchhoff Index of Bicyclic Graphs

2017 ◽  
Vol 60 (1) ◽  
pp. 197-205 ◽  
Author(s):  
Zikai Tang ◽  
Hanyuan Deng
Keyword(s):  
Connected Graph ◽  
Minimum Degree ◽  
Kirchhoff Index ◽  
Resistance Distance ◽  
Degree Of Vertex ◽  
Vertex Set ◽  
Maximum And Minimum Degree ◽  
Bicyclic Graphs

AbstractLet G be a connected graph with vertex set V(G).The degree Kirchhoò index of G is defined as S'(G) = Σ{u,v}⊆V(G) d(u)d(v)R(u, v), where d(u) is the degree of vertex u, and R(u, v) denotes the resistance distance between vertices u and v. In this paper, we characterize the graphs having maximum and minimum degree Kirchhoò index among all n-vertex bicyclic graphs with exactly two cycles.

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